Well, I'd say something is missing here. To clarify, I am certainly not calling you a "marketist", Dave! You support the same kind of markets that I see as good and helpful as they are, just as I have already make clear. To understand what market fundamentalism is, I start from https://en.wikipedia.org/wiki/Market_fundamentalism — this is not, per se, about who controls things, it's about one feature of political economics: that (individual) people, free to choose what to buy with their fiat currency in their own self-interest, will provide the "invisible hand" that leads to prosperity for all. Which, I suggest, makes no sense.
Now, yes, of course, this is then captured by neo-liberalist capitalism so that we get wealth extraction etc. etc., but to me this seems distinct from the idea of market fundamentalism (though easily conflated).
What I see happening in farmers markets, and the like, is that people are buying and selling stuff not solely on the basis of price, but including ethics, values, personal relationship, local economy, etc. And this is clearly not market fundamentalism.
I'm saying that having markets, by itself, is neither good nor bad. I'm also saying that the more you restrict markets to price as the only factor in decisions, the more I see it as open to capture by capitalist players.
There is another thread of potential critique of markets, which is who controls the marketplace? I see this even in the local, small-scale food markets that I see and sometimes participate in here. On a small scale, the marketplace is facilitated by some software for which the person running the market has to rent. Extraction happens in a different way. Scale this up and you can see the similarity with Varoufakis's techno-feudalism. And recall the history of marketplaces … you had to get the monarch's permission to hold markets. Okay, that is fortunately not there (is it?) for farmers markets, but there are vulnerabilities here. And, having said that, do we really believe that unregulated marketplaces are workably good? I assume not; but then, what features of markets are essential to their being a force for good (and, by the by, aligned with Commons interests); or what precautions need to be put in place to ensure that marketplaces are not captured or misused?
I come back to maintaining my position that "markets" seen broadly are neither good nor bad, but that "marketism" or "market fundamentalism" is a real problem which we have to guard against, along with guarding against markets, or marketplaces, even if local, being used as a means of extraction or exclusion.